Earth formation fluid sampler



Feb. 27, 1962 J. w. KlsLlNG 1u EARTH FORMATION FLUID SAMPLER Filed June 4, 1958 A INVENTOR. dames VV. A05/H7?, E'

/l WOR/VE y 3,022,826 EARTH FOTION FLUID SAMPLER James W. Kisling Hl, Houston, Tex., assigner t Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas Filed .lune 4, 1958, Ser. No. 739,865

Claims. (Cl. 166--100) This invention relates nto apparatus for investigating earth formations and, more particularly, to a new and improved earth formation fluidsampler.

One type of fluid sampling apparatus heretofore employed includes a sample-retaining cylinder having a piston disposed therein. Initially the piston is positioned at one `end of the cylinder anda cushion linid fills the remainder of the cylinder. The opposite end of `the cylinder is connected by a flow-controlling orifice to a low pressure chamber. In operation, the fluid sampler is lowered through a borehole to a position adjacent a formation of interest and at the desired level. Formation fluid is then permitted to flow into 'the rst-mentioned end of the sample-retaining cylinder so that the piston moves in response to admittance of connate iluid at a rate determined by the size of the orice, the viscosity of the cushion fluid and the pressure differential between the formation pressure and the pressure ofthe low pressure chamber. After a suilicient sample has been obtained a valve is closed entrapping a fluid sample between the valve and piston and the apparatus` is raised to the sur-face wherev the sample may be recovered. Reference for this type apparatus may be made to the patent granted to L. S. Chambers, No.

2,674,313, issued April 6, 1954. While the apparatus is quite satisfactory and has gained a considerable measure of commercial success, the cylinder and piston must be machined with precision and are thus expensive to manufacture. curred when the moving parts become worn from use in -various -borehole fluids. Additionally, the sample quantity depends to a large extend upon the length of the cylinder which is, in turn, limited by the length of cylinder housing which can be machined with any degree of precision.

. yIt is, therefore, an important object of this invention to provide `a new and improved sample-retaining apparatus for an earth formation linid sampler of simple and inexpensive construction.

It is another object of this invention to provide a new and improved sample-retaining apparatus for use in a sample taker that is relatively trouble-free and inexpensive to maintain in operation.

' I-t is a further object of this invention to provide a new and improved sample-retaining chamber vwhich allows larger quantity samples to be conveniently obtained than heretofore possible. z

1 These and other objects of the invention are attained by means of a sample taker having a portion thereof defining a chamber and a sample-admitting opening for receipt of a uid sample. A flexible sample-receiving member has inner and outer surface portions with the inner portion adapted to be placed `in fluid communication with the sample-admitting opening whereby the member may eX- pand upon receipt of a iluid sample. Pressure control means are associated with the outer surface portion to regulate the expansion of the enclosure means.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings in which:

' FIGS. 1 and 2 represent, in partial longitudinal section,

Moreover, expensive reworking costs are ini a fluid sampler embodying the present invention shown in respective portions of a cycle of operation;

FIG. 3 is a cross-sectional view of FIG. 1; and

FIG. 4 is a View in partial iongimdinai section of 'asf other embodiment of the invention.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, FIGS. 1 and 2 disclose a uid sample taker of the general type shown in the aforesaid Chambers patent however embodying new and improved sample-retaining apparatus of the present invention. tFor specific details of the sample taker not hereinafter described, reference may be made to the Chambers patent for a complete description thereof.

As shown in FIG. l of the drawings, a pressure resistant housing 10 is adapted to be passed through a borehole 11 containing a column of liquid 12. Housing 10 may be, for convenience in handling, divisible into a plurality of separate sections coupled together in any conventional manner, for example by the usual threaded joints. Thus, housing 10is divided into a cable head section 13 which is attached to a conventional electric cable 14, a sampleretaining section 15, a sampling section 16 and power section 17 for operating the sampling section 16.

Sampling section 16 includes a back-up shoe 18 and sampling shoe 19, the latter having a frangible port-plug 21 threadedly received within an opening 22. The backup shoe 18 has an opening 24 for access to the interior of section 16. The raising and lowering of the housing 10 through the borehole 11 to the level of interest is accomplished by means of a winch (not shown) which spools the cable 14 and thus .the housing may be lowered to a depth at which section 16 is adjacent an earth formation 25 from' which -a sample is desired.

Sampling shoe 19 is comprised of a plate member of essentially semicircular configuration in horizontal cross section having front surface 23 faced with a rubber layer 26. Pistons 27, 28 extending rearwardly from shoe 19 are received within hydraulic actuating cylinders 29, 30, respectively, in the housing lil. A gun block 31 also extends rearwardly from shoe 19 and has an opening 32 therein which threadedly receives gun barrel 33. Opening 32 is valigned with the threaded opening 22 for plug 21 and with an opening 34 in the rubber layer 26. A powder charge 35 contained in gun bore 36 is adapted to propel projectile 36 through frangible plug 21 and penetrate the formaiton after the shoe 19 is positioned against the formation.` Suitable means (not shown) for detonating the charge 35 are provided and may be, for example, of the hot-wire type. An opening '37,and a conduit 37' provide a uid communication path between the gun bore 36 and the sample-retaining section 15.

Back-up shoe 18 is a plate of essentially semicircular coniigurationin horizontal cross section and is provided with pistons 38, 3 9 extending from its rear surface into hydraul'lcactuating cylinders of the housing 10 only one thereof being shown at 40.

The actuating cylinders of the housing are connected to hydraulic power means (not shown) in the power section 17 by means of channels 42 so that tluid under pressure may be introduced in the actuating cylinders thereby causing pistons 27, 28, 38, 39 to urge the shoes 18, 19 outwardly to contact the borehole wall. Springs 43 facilitate retraction ofthe shoe members when the hydraulic pressure for the cylinders is relieved.

v Sample-retaining section 15 of housing 10, in which the present invention is embodied, includes a tubular portion 45 of the housing which extends between the sampling section 16 and the threadedly-connected cable head 13. Portion45 receives a sample-retaining unit 48 which may amaze-f taken along lines 3--33' be removed with a collected sample for analysis. The unit 48 includes an upper end plug 49 threadedly received in the upper end of a tubular member 50 which defines an upper pressure chamber 5,1. A valve sub 52 is threadedly connected to the lower end of tubular member 50 and to the upper end of a tubular member 53 dening a lower chamber 54. Threadedly connected to the lower end of tubular member 53 is a seal valve sub 55 fluidly connecting the lower chamber 54 to conduit 37 which as mentioned earlier, is connected via opening 37 to gun bore 36.

The valve sub 52 between chambers 51 and 54 comprises means to regulate the expansion of an enclosure member 56 to be described more fully hereinafter and has openings 57, 58 fluidly connecting the two chambers. A spring-biased plug member 59 normally closes the opening 57 and, by means of the check valve thus formed, a predetermined pressure differential between the chambers 51 and 54 is required before the plug member will open the passage 57, 58. Of course, any suitable iiowcontrol orifice or choke of known construction may be used to regulate the rate of fluid ow between chambers 54 and 51, taking into account, the viscosity of the fluid under control and the pressure diiferential as is well known.

Seal valve sub 55 provides a fluid communication path between the aforementioned conduit 37 and the sampleretaining enclosure 56 of the present invention. Sub 55 includes upper and lower members 55a, SSI; threadedly connected together. Lower member 55b includes a cylindrical chamber 62 having upper and lower passages 63, 64. Spaced balls 66, 67 are resiliently biased by a compression spring toward the passages 63, 64 and adapted to block the passages in one direction of uid ow. Ball 67 normally resiliently blocks lower opening 64 while ball 66 is held intermediate of the passages 63, 64 by means of a rod 68 extending transversely into the chamber 62. The transverse rod 68 is attached to a piston 69 contained in another chamber 70 and a spring is positioned behind piston 69 normally forcing rod 68 into chamber 62 thereby retaining ball 66 in the position shown. In front of piston 69, the chamber 70 contains a small explosive charge 73 which is electrically connected by wires (not shown) to a switch at the surface so that actuation of the switch will cause the charge to be detonated hence increasing the pressure within charnber 70 and forcing piston 69 to compress the spring and release ball 66 whereby the passage 63 may be closed. The upper member 55a has a central passage 74 uidly connected to the passage 63 and its upper end is connected to a passage 75 of a threadedly-connected coupling member 76.

The upper end of coupling member 76 is received within an end opening of the enclosure member 56 and has grooves 61 therein for receipt of projections on the inner surface of the enclosure member. The retaining enclosure 56 is in the form of an inverted bag of a suitable flexible material, such as neoprene, which can withstand borehole pressures and temperatures. Preferably the bag material is of resilient as well as flexible construction so that the bag tends to retain a Hat elongated form but is capable of expanding. Thus, the enclosure before receiving the uid sample is normally collapsed with inner surface portions in Contact as shown at 56a (FIG. 3). Receipt of connate fluid by the inner surface portions from the fluid sampler opening will cause the member 56 to open or expand as shown in FIG. 2. A suitable clamping means 78 is provided to secure the enclosure 56 to the coupling member 76.-

The device is arranged for operation by assembling the component elements of the device in the aforesaid relationship. The sample-retaining unit 48 is assembled in the following manner. The collapsed enclosure member 56 and the tubular housing 53 are threadedly coupled to the upper member 55a in the above-described order.

Next a uid cushion liquid 77, such as water, is introduced to the chamber 54 and surrounds the outer surface portions of the enclosure 56. Sub 52, tubular member 50 and end cap 49 are then threadedly connected to the unit so that chamber 51 contains only air at atmospheric pressure. The unit 48 is then inserted into the cylinder 45 to enable uid connections of the lower valve member 55b with the conduit 37 and the mechanical connec tion of the collar member 13 with the tubular member 45.

Thereafter, the device is lowered by the cable 14 to the level of interest, power section 17 actuated, and the shoes 1S, 19 moved into engagement with the walls of the borehole as shown in FIG. 2. Detonation of the charge 35 causes the projectile 36 to rupture plug 21 and penetrate the formation, and formation uid under formation pressure will pass through the opening in plug 21, channel 36, conduit 37' and valve 55 to the retaining enclosure 56. As the sample is introduced to the inner surface portions of the retaining enclosure 56, the enclosure expands or opens because the formation pressure is higher than the air pressure in chamber 51. Hence, the expanding outer surface portions displace the cushion fluid 77 through the check valve 52 into the upper chamber 51. The iluid sample will continue to enter the retaining enclosure 56 until there is a pressure equilibrium between the upper and lower chambers 51, 54 which effectively limits the amount of sample obtained. The volume of chamber 51 should, of course, be such that the pressure equilibrium is reached before all of the cushion uid 77 is displaced so that the retaining enclosure 56 does not over-inflate or block passage 58. After the iluid sample is obtained, the opening to the sample enclosure 56 is closed by actuating the charge 73 of the valve section SSb hence causing ball 66 to block passage 63. Shoes 18, 19 are then retracted and the device may be recovered from the borehole to enable analysis of the collected sample.

From the foregoing it should be readily apparent that this invention has provided a fluid-retaining member for a fluid sampler having an inner surface portion fluidly connected to a sample-admitting opening for receipt of connate uid, an outer surface portion and pressure regulating means associated with the outer surface portion adapted to regulate quantity of connate fluid contained within the inner surface portions. Since cylinder 53 does not receive a sliding piston, it need not be accurately machined. Moreover, enclosure 56 can be constructed in a simple manner not requiring precision techniques of manufacture. Accordingly, a fluid sample taker embodying the invention is inexpensive to fabricate though entirely efficient and reliable in operation. In addition, enclosure 56 is not subject to undesirable wear as would a piston arrangement; however, in the event replacement of the enclosure is desired, this can be accomplished easily and inexpensively.

As shown in FIG. 4 a number of enclosures 80, 81 may be successively connected together. Each enclosure has a lower opening for receiving a coupling member 76 which has a male threaded portion while an upper opening receives a coupling member `82 having a femalethreaded portion. It is readily apparent that a number of enclosures may be connected together in a series relation and that the housing made up in a number of sections 84, 85 suitably coupled by member 86. This allows a substantially larger iluid sample to be taken in a longer cylinder which would ordinarily be economically impractical to machine. The end enclosure of the series,l

of course, is suitably capped by means of a female threaded plug 87. Of course, the upper chamber must be suitably increased to accommodate the displacement of the uid cushion.

If desired, member S6 may be suitably stiff so as to retain the position shown in FIG. 1. Alternatively, it will be appreciated that the member 56 may be flexible but not resilient and may be initially collapsed at the bottom of chamber 53 or may be of cylindrical form and arranged to stretch as it expands. Hence, the term expand may be cons dered synonymous with the opening o? member 56upon receipt of a fluid sample. It will also be apparent that while the attachment of membery 56 to the coupling member '76 istillustrated as a clamp means, the members could be suitably bonded together.

While various embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from the scope of this invention `in its broader aspects and.therefore, the aim in .the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is: t

1. In a fluid sample taker adapted to be lowered in a borehole, a sample retaining portion defining a chamber and having a sample-admitting opening; a normally collapsed and flexible enclosure member for receiving a fluid sample disposed in said chamber, said member having inner and outer surface portions, said inner portion in a collapsed position being in substantially contacting relation whereby the volume defined within said inner portion is substantially zero; means to place said inner portion in fluid communication withV said sample-admitting opening whereby said enclosure may expand from a collapsed position to an extended position; and hydraulic means associated with the outer surface portion of said enclosure including a fluid and flud-retarding means whereby the expansion of said enclosure uponrreceipt of a fluid sample is regulated.

2. In a fluid sample taker for use in a well or borehole, a sample retaining portion defining a chamber and having a sample-admitting opening for receipt of a uid sample, an elongated, normally collapsed flexible member in said chamber having inner and outer surface portions, said inner surface portion in a collapsed position being in substantially contacting relation whereby the volume defined within said inner portion is substantially zero, means tov place said inner portion in fluid communication with said sample-admitting opening whereby a fluid sample may be entrapped by said inner surface portion as said member expands from a collapsed position to an extended position, and hydraulic meansY associated with said outer surface portion and adapted to regulate the expansion of said enclosure means.

3. In a fluid sample taker for use in a well or borehole, a body having a sample retaining portion defining first and second chambers and having means defining a normally closed sample-admitting opening for receipt of a fluid sample; an elongated normally collapsed flexible member disposed within said irst chamber having one portion of an inner surface adapted to be placed in fluid communicationwith said sample-admitting opening, and having another portion of said inner surface in a contacting relationship whereby said member is in a collapsed position, said contacting inner surface portion adapted to expand outwardly thereby to receive and entrap a fluid sample; means to place said sample-admitting opening in fluid communication with said inner surface; means to regulate the rate of expansion of said enclosure ,includng a flow-control device providing a fluid communication path between said first and said second chamber and a cushion fluid disposed between said outer surface portion of said flexible member and said flow-control device; means` to open said sample-admitting opening whereupon separation of said contacting inner surface portion'of said flexible member causes displacement of the cushion uid from said first chamber to said second chamber through said flow-control device.

4. In a fluid sample taker adapted to be lowered into a borehole a sample retaining portion of said sample taker defining a chamber and having a sample-admitting opening; a plurality of normally collapsed flexible fluid enclosure members disposed in said chamber and having inner and outer surface portions said inner portions being in contacting relationship in the collapsed position of said members; means fluidly connecting said inner surface portions of said members in series ow relation, means to place at least one ofsaid enclosure members in fluid communicaton with said sample-admitting opening, and means associated with the outer surface portions of said enclosure members including a fluid and fluid retarding means for regulating the expansion of said enclosure members upon receipt of a fluid sample through said sample-admitting opening. v

5. A sample taker for obtaining a fluid sample from earth formations traversed by a well bore, comprising a housing having a sample retaining section defining a chamber and having a sample-admitting opening, an expansible bag-l kev enclosure within said chamber, means for placing the interior of said enclosure in fluid communication with said opening to receive a fluid sample from earth formations adjacent thereto and to expand from a collapsed position, said chamber having a volume of liquid confined therein and surrounding said bag in its collapsed position, means in said housing for regulating displacement of said liquid as said enclosure expands to retard entry of said fluid sample into said enclosure, and means for retaining the fluid sample receved in said venclosure for withdrawal from the well bore.

References Cited in the file of this patent UNITED STATES PATENTS 

